The present nonprovisional application claims priority under 35 USC 119 to Japanese Patent Application No. 2002-170212 filed on Jun. 11, 2002 the entire contents thereof is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a flap operating system for operating left and right flaps mounted respectively on left and right main wings synchronously with each other.
2. Description of Related Art
A conventional flap operating system is designed so that flaps mounted on left and right main wings are connected to and operated by corresponding hydraulic actuators. In order to compensate for a subtle difference between strokes of the left and right hydraulic actuators to equalize the lowered angles of the left and right flaps to each other, the left and right hydraulic actuators are connected mechanically to a synchronizing mechanism. The synchronizing mechanism comprises two cables wound in an X-shape around left and right pulleys connected to and rotated by the left and right hydraulic actuators, so that the rotational angles of the pulleys, namely, the contracted positions of hydraulic cylinders are equalized forcibly to each other.
There is a steering system adapted to operate a steering surface by a hydraulic actuator, which is known from Japanese Patent Application Laid-open No. 5-97095, wherein when the hydraulic actuator is defective, the emergent steering of the steering surface can be achieved by an electric actuator disposed in series to the hydraulic actuator.
In the conventionally known system in which the left and right hydraulic actuators for operating the left and right flaps are operatively connected to each other by the synchronizing mechanism, the following problem is encountered: When an abnormality is generated in one of the hydraulic actuators to bring it into a free state in a state in which the flaps have been lowered, aerodynamic loads acting on the left and right flaps are applied concentratedly to the other hydraulic actuator and a powder transmitting system for the other hydraulic actuator and thus, an excessive load is applied to the flap operating system or a main wing structure such as a spar and a rib. Another problem is that when the other actuator is operated in a state in which the one actuator has been stuck due to the abnormality, an excessive load is applied to the main wing structure or the flap operating system due to a load applied to the other actuator.
Accordingly, it is an object of the present invention to provide a flap operating system for operating left and right flaps synchronously with each other by left and right actuators, wherein, when a hydraulic actuators is abnormal, the excessive load is previously prevented from being applied to the main wing structure or the flap operating system.
To achieve the above object, according to a first feature of the present invention, there is provided a flap operating system for operating left and right flaps mounted on left and right main wings synchronously with each other, comprising left and right hydraulic actuators for driving the left and right flaps, respectively, left and right pulleys connected to and rotated by the left and right hydraulic actuators, and first and second synchronizing cables which connect the left and right pulleys in an X-shape to each other to synchronize the rotations of the left and right pulleys, the system further including left and right rotational angle sensors for detecting rotational angles of the left and right pulleys, respectively, and a control means adapted to calculate a difference between the rotational angles detected by the left and right rotational angle sensors and to stop the operations of the hydraulic actuators when the difference exceeds a predetermined threshold value.
With the above arrangement, in the flap operating system in which the left and right hydraulic actuators for operating the left and right flaps respectively are connected to the left and right pulleys around which the first and second synchronizing cables are wound in the X-shape, in order to synchronize the rotations of the left and right pulleys with each other, the operations of the hydraulic actuators are stopped when the difference between the rotational angles of the left and right pulleys exceeds the predetermined threshold value due to any abnormality. Therefore, it is possible to prevent an excessive load from being applied to a main wing structure or the flap operating system due to aerodynamic loads applied to the flaps or hydraulic loads generated by the hydraulic actuators. Thus, it is unnecessary to enhance the rigidity of the various components to a level more than required in consideration of the excessive load. This can contribute to a reduction in weight of a main wing and a reduction in cost.
According to a second feature of the present invention, in addition to the first feature, each of the pulleys includes a pulley body, an oscillation arm pivotally supported at its intermediate portion for oscillation relative to the pulley body, and a locking member adapted to lock the oscillation arm at a predetermined location relative to the pulley body and to permit the oscillation of the oscillation arm relative to the pulley body when a load applied to the oscillation arm exceeds a predetermined value; the first synchronizing cable connects one end of the oscillation arm of the left pulley and the other end of the oscillation arm of the right pulley to each other; and the second synchronizing cable connects one end of the oscillation arm of the right pulley and the other end of the oscillation arm of the left pulley to each other, whereby when the oscillation arm is oscillated relative to the pulley body of one of the left and right pulleys, the difference between the rotational angles detected by the left and right rotational angle sensors exceeds the threshold value.
With the above arrangement, the pulley is comprised of the pulley body and the oscillation arm pivotally supported for oscillation relative to the pulley body, and the oscillation arm is locked at the predetermined location relative to the pulley body by the locking member, so that the oscillation of the oscillation arm relative to the pulley body is permitted when the load applied from the first synchronizing cable or the second synchronizing cable to the oscillation arm exceeds the predetermined value. Therefore, when the tension of any one of the first and second synchronizing cables is increased due to an abnormality, the oscillation arm is oscillated relative to the pulley body of one of the pulleys, whereby a difference can be generated between the rotational angles of the left and right pulleys.
Resolvers 41 and 42 in each of embodiments correspond to the rotational angle sensors of the present invention, and an electronic control unit U in each of the embodiments corresponds to the control means of the present invention.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.